1. Field of the Invention
This invention relates generally to systems and methods for image acquisition and, more specifically, to systems and methods for collecting computed tomography (CT) image data.
2. Background of the Invention
Computed tomography is an imaging technique that has been widely used in the medical field. In a procedure for computed tomography, an x-ray source and a detector apparatus are positioned on opposite sides of a portion of a patient under examination. The x-ray source generates and directs a x-ray beam towards the patient, while the detector apparatus measures the x-ray absorption at a plurality of transmission paths defined by the x-ray beam during the process. The detector apparatus produces a voltage proportional to the intensity of incident x-rays, and the voltage is read and digitized for subsequent processing in a computer. By taking thousands of readings from multiple angles around the patient, relatively massive amounts of data are thus accumulated. The accumulated data are then analyzed and processed for reconstruction of a matrix (visual or otherwise), which constitutes a depiction of a density function of the bodily section being examined. By considering one or more of such sections, a skilled diagnostician can often diagnose various bodily ailments such as tumors, blood clots, etc.
A problem associated with existing CT imaging systems is that a patient may not feel comfortable confined within a gantry opening, especially when the image data collection procedure takes too long. Mechanical configuration and/or regulatory rules may limit the rotation rate of a gantry on which the x-ray source and the image detector are mounted. Some of the existing CT imaging devices have gantry speed that is limited to one rotation per minute. Although some of the existing CT scanners can be configured to rotate about a patient faster, the volumetric data set generated from such scanners may have motion artifacts between slices.
Another problem associated with existing CT imaging systems is that a slice thickness is generally larger than a resolution of a pixel within a slice. For example, an existing CT imaging system may generate a slice every 1 centimeter, while a resolution of a pixel within a slice is 0.5 millimeter. In order to create better resolution between slices, scanners have been developed that has an increased number of detectors in the Z-axis (axis of rotation) direction. However, increasing the number of detectors in the Z-axis increases the manufacturing cost of the detector, which is already quite expensive as it is based on traditional single crystal silicon electronics coupled to x-ray converters.
For the foregoing, improved apparatus and method for collecting CT image data and generating CT images would be desirable.